The Onderon Great Dynasty was an integral part of the Imperial Republic, owing to the dynastic aspirations of famed Selkast General Horten. For a brief moment in galactic history a huge swath of the galaxy was ruled by a single dynasty, as PGA Chancellor Selkisto Horten presided over the restoration of the Republic on Coruscant, held joint control over the Velmor Military Engineering Works ("VMEW") with Senator Tiffany Vandergraff, place his daughter Calliope (Empress Calli) on the temporarily vacant Fel Throne, while Calliope herself held both the office of Talus PGA Senator and Princess Regent of Onderon. This gave Chancellor Horten momentary control over the Galactic Senate, the Fel Throne, the throne of Onderon, as well as the powerful Velmoran Oligarchy.
With behind the scenes support from the Coruscant Sector H-88 branch of the Intergalactic Banking Clan, Chancellor Horten stood as one of the richest and most powerful dynasty in the galaxy. This power would begin to diminish with the abdication of Empress Calli, the destruction of the Onderon Port of Iziz by the Sith marauder "Ravens Harvest," and finally the occupation of Coruscant by the Revenant Armada.